title: Genetic ablation of V2a ipsilateral interneurons disrupts left-right locomotor coordination in mammalian spinal cord.
abstract: The initiation and coordination of activity in limb muscles are the main functions of neural circuits that control locomotion. Commissural neurons connect locomotor circuits on the two sides of the spinal cord, and represent the known neural substrate for left-right coordination. Here we demonstrate that a group of ipsilateral interneurons, V2a interneurons, plays an essential role in the control of left-right alternation. In the absence of V2a interneurons, the spinal cord fails to exhibit consistent left-right alternation. Locomotor burst activity shows increased variability, but flexor-extensor coordination is unaffected. Anatomical tracing studies reveal a direct excitatory input of V2a interneurons onto commissural interneurons, including a set of molecularly defined V0 neurons that drive left-right alternation. Our findings imply that the neural substrate for left-right coordination consists of at least two components; commissural neurons and a class of ipsilateral interneurons that activate commissural pathways.
authors.affiliation: Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Crone
authors.forename: Katharina A
authors.initials: KA
authors.lastname: Quinlan
authors.forename: Laskaro
authors.initials: L
authors.lastname: Zagoraiou
authors.forename: Steven
authors.initials: S
authors.lastname: Droho
authors.forename: Carlos Ernesto
authors.initials: CE
authors.lastname: Restrepo
authors.forename: Line
authors.initials: L
authors.lastname: Lundfald
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Endo
authors.forename: Jennifer
authors.initials: J
authors.lastname: Setlak
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jessell
authors.forename: Ole
authors.initials: O
authors.lastname: Kiehn
authors.forename: Kamal
authors.initials: K
authors.lastname: Sharma
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D018398:Homeodomain Proteins / Q000235:genetics; D007395:Interneurons / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009043:Motor Activity / Q000235:genetics / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011995:Recombination, Genetic; D013116:Spinal Cord / Q000502:physiology*; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors; C088975:Vsx2 protein, mouse